Why Won't Compound Glazing Stick?

Old Compound on Windows

• Before applying new glazing compound to your windows, scrape away any remnants of the old sealant. Leaving old, cracked and peeling glazing can prevent your new glazing from contacting wood surfaces. Without this contact, the new compound glazing can't dry properly and adhere to the surface. Pry chunks of the old sealant away from glass panes using a putty knife. Use a heat gun to soften areas of dry glazing that resist your attempts to cut them away.

Use More Glazing

• Apply a liberal helping of glazing compound to the cracks you're trying to seal on your windows and frames. You need a generous helping of sealant to ensure the glaze seeps into the spaces, and contacts the wooden surface. Using only a small amount of glaze may prevent the compound from adhering properly. Once you have sufficient glaze in the crevices of your windows and frames, you can clear the excess away by scraping it off with your putty knife. Proceed methodically to ensure you don't damage the wood or accidentally break a pane of glass.

Smoothing Rough Edges

• Smooth the glazing compound with a putty knife dipped in mineral spirits. This will keep the glazing from drying on your knife and allows you to spread the compound evenly across the surface. A smooth layer of glazing compound adheres better and dries faster because it achieves a uniform density across the entire crack or crevice. It may take more than one pass with your putty knife to smooth out the compound's surface. Dip your knife in mineral spirits and continue the procedure until you have a smooth, even layer across the given area.

Painting Over Too Soon

• Painting over glazing compound too quickly can slow the hardening process dramatically. Glazing compound requires at least a full day to dry completely. Just because the compound feels hard doesn't mean the surface underneath isn't still pliable. Failing to provide adequate drying time for the glazing compound can increase its drying time from days to years. This may also damage the compound's ability to adhere to your windows, resulting in more gaps and cracking paint.